Thursday, April 3, 2014

Species That Don't Get Enough Publicity #6: Moropus

The thing about the featured animal today is you’ve probably
seen it before. There’s a lot of museums with it-the Harvard museum, Yale
Peabody museum, Field Museum, Denver museum,
Smithsonian National Museum,
Carnegie museum, and American museum each have a mount of it. There are
multiple mounts at the place of its discovery, the Agate
Fossil Beds
National Monument in Nebraska. I’m sure most of you have seen
this one and wandered past it, thinking it a horse or a big bizarre mammal. It
is a big, bizarre mammal, but it’s one that’s one of my favorites. This is
Moropus, 5 species of a large, successful mammal that roamed the American west.

Moropus was first discovered in 1877, as part of the great
paleontologist Othniel Charles Marsh’s endless quest for fossils.In that season, he found the rodent Allomys,
the rhinoceros Diceratherium and Amynodon, specimens of bison, the Cretaceous
bird Austinornis, the Jurassic crocodile Diplosaurus, the small ornithopod
dinosaur Nanosaurus, the prehistoric stingray Heliobatis, and this new curious
mammal. This was in the middle of the famous Bone Wars. At this time, Marsh and
his archrival Edward Drinker Cope tried to outdo each other in terms of naming
and describing prehistoric animals. While the dinosaurs like Triceratops,
Stegosaurus, Camarosaurus, Allosaurus, Apatosaurus and their less famous kin
have gotten the main press both now and then, the “Bone Wars” extended to
mammals-Uintatherium and Megacerops, among other species, had mountains of
synonyms erected by the competition of the rival geniuses. They spent their
extensive family fortunes entirely on paleontology, and left the world very
poor, bitter, and tired, but enriched both the Yale Peabody Museum (Marsh’s
base) and the Academy of Sciences (Cope’s base) with endless fossils.

Things changed for this genus when James Cook, a partner and
friend of Chief Red Cloud, found fossils on his ranch in northwest Nebraska in the 1870s. He
had also befriended Marsh and Cope in his travels across the west as a cattle
wrangler and gave them whatever fossils he could find. This really took off
when his son Harold struck up a deal with the eastern museums in the 1920s. For
a modest fee, he provided access to paleontologists O.A. Peterson of the
Carnegie museum, Erwin H. Barbour of the University of Nebraska,
and Henry Fairfield Osborn of the American museum. His career also encompassed
the infamous mistake Hesperopithecus, a poorly preserved peccary tooth mistaken
for a prehistoric human tooth by the overenthusiastic Osborn. W. K. Gregory
managed to prove it as part of the Miocene peccary Prosthennops, a
decision accepted by the rest of the scientific community, but Osborn stuck by
his ape-man for the rest of his life.

At Cook’s ranch, which he eagerly turned into a national park, New England’s paleontologists unveiled the complete
animal, a truly bizarre chimera of ungulate affinities. It was a chalicothere,
a family of extinct herbivores distantly related to today’s horses, rhinoceros,
and especially tapirs. Chalicotheres had been known for almost a century before
these discoveries, but no where near in this state of preservation.
Chalicotheres were a very successful family-ranging from North America’s
Eoromoropus 40 million years ago in North America to about Ancylotherium 1
million years ago in Ethiopia.

The skull is dramatically different from its relatives. The tip of the
snout, eyes, and the teeth resemble those of a rhinoceros, while the back of
the skull resembles a horse’s.The neck
is shorter and thicker than that of a horse, the front limbs long as a horse’s
but the bones are proportioned like a tapir. The rest of the animal would
resemble a horse (a large, draft horse) but for one thing: claws.

Another interesting trait of the skull is that male chalicotheres have
comparatively higher and thicker skull roofs as a sexually dimorphic trait. (Margery
Chalifoux Coombs

Systematic Zoology Vol. 24, No. 1 (Mar., 1975),
pp. 55-62). Indeed, a later genus, Tylocephalonyx was distinguished for the
small dome on top of its head, like a Pachycephalosaurus. It’s very likely that
male Moropus head-butted like giraffes or goats for social status and sexual
opportunities.

The group of chalicotheres that Moropus is associated with is called
Schizotheriinae for their chimerical trait of claws. Instead of a fleshy (tapirs
and rhinos) or solid (horse) hoof for fast locomotion, the front and back feet
are unfused and tipped with large, curved claws like those of a sloth or a
bear.There has been debate over what
they were used for. One model has them being used as billhooks, pulling down
branches for browsing in a mode of life similar to that of a bear, gorilla,
Therizinosaur, or ground sloth. Another model has them digging for roots and
shoots like an armadillo or pangolin. Of course, all of these clawed animals
can use them for anti-predator defense, and the claws of chalicotheres could be
very powerful weapons if used against the bear dogs and entelodonts that could
threaten it.

The long limbs, the large claws, and the wear patterns on their teeth (http://www.wired.com/2010/11/pass-the-twigs-please-toothwear-indicates-the-variety-of-chalicothere-diets/)
indicate that they were browsers, again like bears, gorillas, Therizinosaurs,
and ground sloths. The difficulty is that bears usually don’t use their claws
to browse, and gorillas and pandas eat very different kinds of plants than
Moropus. This is a niche that has not existed for 10,000 years, as most living
browsers have no need of claws to grasp branches and instead rely on long necks
and snouts.There have been
reconstructions of Moropus having a short trunk like its tapir relatives, but
the nasal cavity is far too small and positioned forwards for a trunk to be
likely.

The fact that browsers were still fairly successful explains a great
deal about the paleoenvironment. In the Early Miocene, the earth was still warm
despite the gradual cooling since the late Eocene, and grasses became the top
plant. North America in the Miocene would have been similar to the savannas of
tropical Africa and India. The Miocene was also a peak in animal diversity,
with many species from many families coexisting.

There are four well-known species of Moropus, and two
obscure ones.M. matthewi is poorly
represented in the fossil record and probably dubious, while the Batesland
Formation of about 18 mya has several unassigned specimens of Moropus.

Moropus elatus is the biggest and best known of the species
of Moropus, being found in Nebraska and Colorado in the late Arikarrean and
early Harrisonian ages, about 20-18 mya. This is the species we see in New
York, Chicago, Washington and Pittsburg. It shared its environment with the oreodonts (small,
piggy artiodactyls) Merychyus,
Merycochoerus, Merycoides, and Hypsiops, palaeomerychid (horned, deerlike artiodactyl)
Aletomeryx, the peccary Thinohyus, the horses Kalobatippus. Parahippus, and Desmatippus, the small, possibly synonymous
rhinosMenoceras and
Diceratherium, the bear dogs Cynelos,
Daphoenodon, Temnocyon and Ysengrinia, the hyena-like dogs Cynarctoides, Phlaocyon, Cormocyon,
Desmocyon, and Osbornodon, the relatives of weasellike Promarte and the giant wolverine Megalictis,
musk deer Blastomeryx and Problastomeryx, the giant entelodont (big piglike
relatives of hippos)Daeodon, the
primitive bear Cephalogale, the llama-like camels Michenia, and Tanymykter, the gazelle camel Stenomylus
and the giraffe camel Oxydactylus, the mouse deer Nanotragulus, the gopherlike beaver Palaeocastor,
and the horned antelope-like artiodactyl Syndyoceras.

:

Moropus hollandi is distinguished from elatus by being
smaller and more gracile. However, it lived in the same time period and
environment, and may have been the same species. I know of no mounts of the
animal, and I strongly suspect it may have been a juvenile or female like the
former species Moropus petersoni.

Moropus oregonensis was another small, slender species,
found not on the great plains but in Oregon and Florida during the Arikarrean
and Harrisonian. It’s possible there were denser forests that restricted body
size while supporting thriving populations, or that this new species preceded
M. elatus into North America. Stratigraphy suggests this may be the longest
lived of the Moropus species-being the first to evolve in America and lasting
into the later Miocene, overlapping the time spans of M. elatus and M.
merriami. (Coombs, M. C., Hunt, Jr, R. M., Stepleton, E., Albright III, L. B.
& Fremd, T. J., 2001: Stratigraphy, chronology, biogeography, and taxonomy
of Early Miocene small chalicotheres in North America. – Journal of
Vertebrate Paleontology: Vol. 21, #3, pp. 607–620) Species it coexisted with included the piglike
Agriochoerus, the palaeomerychid Barbouromeryx,
the camels Gentilicamelus,
Poebrotherium, Nothokemas, and Paratylopus, entelodonts Archaeotherium and Daeodon,
the mouse deer Hypertragulus,
Leptomeryx, and Nanotragulus, the musk deerPseudoblastomeryx, the oreodonts Eporeodon, Merycochoerus, Merycoides,and
Paroreodon, the bear dogs Daphoenus,
Daphoenodon, and Amphicyon , the hyena-like dogs Rhizocyon, Cormocyon, Cynarctoides, Phlaocyon, and Desmocyon,
the mustelid Oligobunis the
paramarsupial Herpetotherium, the insectivore Micropternodus, the rabbit
Palaeolagus, the horses Kalobatippus, Miohippus, Archaeohippus,
Parahippus, and Anchitherium, the tapir Nexuotapirus, the beavers Meniscomys, Schizodontomys, and Hystricops,
the gopher Entoptychus, the pocket mice

Proheteromys,
Arikareeomys, Texomys, and Harrymys, the mouse Leidymys, the squirrel Protosciurus,
the hedgehogs Parvericius and Centetodon, the rhino Menoceras, and the basal
rodent Mylagaulodon

The last species is Moropus merriami from Nebraska and
Nevada, surviving as late as 15 million years ago.Again, there are no known mounts of the
animal.It lived during the Barstovian
period, where the forests of North America receded even more as the earth
cooled and dried. Part of its problem were that horses and camels were thriving
as the grasslands covered the plains, while new species of probiscideans came
in from Asia, taking over the browsing role. Moropus has always been found in
very warm, wet environments which became more and more rare. It is unlikely
they would have survived the Pliocene and Pleistocene, as earth cooled even
more and the chalicothere niche in the New World was firmly usurped by ground
sloths. Other animals of the area were the pronghorn Merycodus
and Paracosoryx, the camels Miolabis
and Paramiolabis, the musk deer Blastomeryx
and Parablastomeryx, the oreodonts Brachycrus, Merychyus, Ticholeptus and Brachycrus, the palaeomerychids:
Bouromeryx, Dromomeryx, and Sinclairomeryx, the proceratid Lambdoceras, the peccaries
Aptenohyus, Hesperhys, and Thinohyus, the
bear dogs Amphicyon, Cynelos, and Pliocyon, the bone-crunching dogsEuoplocyon, Microtomarctus, Osbornodon, Psalidocyon,
Tomarctus, Protomarctus Paracynarctus, Aelurodon, Metatomarctus, and Cynarctoides,
the dog Leptocyon, the cat Pseudaelurus, the badger Plionictis, the horses Desmatippus,
Merychippus, Scaphohippus, Hypohippus, and Acritohippus, rhinos Aphelops,
Teleoceras, and Peraceras, the beaver Monosaulax, the basal rodents Umbogaulus,
Alphagaulus, and Hesperogaulus, America’s first mastodon Zygolophodon, the
early bear Ursavus, the poorly named mouse deer Pseudoparablastomery, today’s
modern ringtail Bassariscus and its ancestor Probassariscus, the pocket mouse Apeomyoides,
the rabbit Hypolagus, the pika Oreolagus and the mountain beaver Liodontia.

You can tell by the
sheer amount of names here that mammal diversity was at its height, and Moropus
is symbolic of the weird and wonderful animals that ruled the earth.

Despite its
ubiquity in museums and such, it’s never made a named appearance in a documentary
or movie, and only two small, old toys have been made. One is a kangaroo-shaped
one in a bipedal pose with a bright purple and orange coat by Playvision and
can still be found in bins (or its knockoffs). The other is a far rarer quadrupedal
sculpt by Starlux. Since Moropus is an archetypical North American prehistoric
mammal and is a frequent sight in prehistory books, its rarity is probably due
to the age-old neglect of Tertiary animals.

It’s weird, it’s big,
and it’s all American, so I would argue that it needs more respect and
awareness. I'm very glad when I see it in media. Fellow fans of the program My Little Pony will be please to find out fans have made loveable Moropus ponies on Deviantartlike these.So Hollywood, give
this guy a break. Museums, keep him on display. Toy companies, here’s a new
fresh face. Authors, think about the crap you’re writing and how this genus
could perk up the place. And remember, shop Moropus where you work or play.

2 comments:

I pretty much agree with Davis's assessment of this animal. I can't remember when I first became aware of it, but is has always fascinated me. Bullyland did make a really nice figure of him. I am not sure if it is still available. We have a great specimen on display at the Denver Museum of Nature and Science, a.k.a Colorado Museum of Natural History. There is a wonderfully amazing diversity of mammal life that we ma view today. But think how great it would be to see some of these prehistoric mammals alive and in the flesh. If I had a time machine I would go back to the age of dinosaurs once just to day I did it. Then I would spend the rest of my days viewing prehistoric mammals. Andy, Denver

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Hi everyone! You may know me already, but 99% of you won't. I've decided to make a blog for myself. I'm a anthropology student who has returned to his original passion for palaeontology. Ever since I was little, I've been fascinated with the weird and wonderful animals that have inhabited our planet and I've made this blog to keep this in my mind and hopefully in yours. Most people blog about their interests, and while I've got a range of interests-see history and anthropology above, not to mention zoology, astronomy, art, cooking, science fiction and fantasy films and literature, and a myriad of others, the one I want to do for a living is the study of Earth's ancient past.

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